This invention relates to an apparatus for testing an oil well, and more particularly relates to a full opening closure valve which operates responsive to annulus pressure and includes a reverse circulation valve, and a full opening sampler valve including a hydraulically controlled closing mechanism.
Various tester valves and samples valves for testing oil wells have been developed over the recent years which are responsive to changes in annulus pressure for opening and closing the valves. Reverse circulation valves responsive either to the operation of an annulus pressure responsive tester valve or responsive themselves to annulus pressure changes have also been developed. For instance, U.S. Pat. No. 3,850,250 issued Nov. 26, 1974 and U.S. Pat. No. 3,930,540 issued Jan. 6, 1975, both to Holden et al and assigned to the assignee of the present invention, disclose a circulation valve which opens after a predetermined number of annulus pressure changes have been applied to the well annulus.
U.S. Pat. No. 3,823,773 issued July 16, 1974 to Nutter discloses a circulation valve which is an integral part of a sampler mechanism wherein the sampler mechanism opens and closes responsive to pressure changes in the well annulus. The circulation valve disclosed therein moves from a closed position to an open position after a predetermined number of operations of the sampler valve. Also pertinent to the present invention is U.S. Pat. No. 3,970,147 issued July 20, 1976 to Jessup et al and assigned to the assignee of the present invention. That patent discloses a circulation valve which moves to a locked open position responsive to an increase in annulus pressure above a given value. One embodiment shows a circulation valve which is an integral part of a sliding sleeve type normally open tester valve, arranged such that the tester valve closes prior to the opening of the circulation valve.
The dual CIP reverse circulating valve offered by Halliburton Services of Duncan, Oklahoma is a reverse circulating valve in which spring loaded fingers hold a sliding sleeve mandrel in a position covering reverse circulating ports in a housing of the valve. The sleeve mandrel is spring loaded toward the open position. The dual CIP reverse circulating valve is operated by drill pipe rotation wherein rotation advances an operating mandrel which also opens and closes a tester valve mechanism. After a predetermined number of rotations the tester valve is closed and additional rotation activates a releasing mechanism which releases the fingers holding the sliding sleeve mandrel. The sliding sleeve mandrel is then moved to the open position by the mentioned spring, thereby uncovering the circulating ports to allow reverse circulation.
U.S. Pat. No. 3,856,085 issued Dec. 24, 1974 to Holden et al and assigned to the assignee of the present invention discloses an annulus pressure operated well testing apparatus which includes a full opening ball valve for providing a fully opened passageway through the testing string to the formation to be tested.
A patent application by Burchus Q. Barrington filed on the same date as the present application and assigned to the assignee of the present application discloses a full opening closure valve which is moved from the normally open position to the closed position by an increase in the pressure in the well annulus above a predetermined level, and includes a circulation valve and a full-opening sampler valve mechanism. The Barrington apparatus was developed independent of and first in time to the present invention except for the particular structure of the activating mechanism for closing the ball valves simultaneously, which is included as the preferred embodiment of both specifications, and which is included in the invention claimed herein.
The apparatus of the present invention is a normally open sampler valve which provides a fully open well testing flow path therethrough, and which is closed under hydraulic control after a predetermined pressure increase in the well annulus pressure. The sampler valve comprises two normally open ball valves connected to an operating mandrel for moving the ball valves to a closed position simultaneously. The sampler is locked, both hydraulically and mechanically, after the ball valves are moved to the closed position.
The operating mandrel is connected to a power mandrel which in turn is frangibly held in a first position until the pressure in the well annulus exceeds a predetermined level. The power mandrel is then frangibly released, and moves toward a second position under the influence of well annulus pressure.
The operating mandrel includes a thickened portion having a flow passage therethrough which, during the movement of the power mandrel from the first position to the second position, transfers a fluid from one side of the thickened portion to the other side. A metering jet in the flow passage controls the rate at which the connected power and operating mandrels move from the first position to the second position. A check valve in the flow passage prevents the operating mandrel from returning back toward the first position.
The movement of the mandrels from the first position to the second position closes the two ball valves to form a sample chamber therebetween. During its movement from the first position to the second position, the power mandrel, the operating mandrel and the ball valves move as a unit. The ball valves are rotated to the closed position by the action of pins mounted on pin arms which are retained in the walls of the sampler housing.
When the power mandrel reaches the second position, the power mandrel and the operating mandrel are disconnected by a disconnecting mechanism. The power mandrel then continues to a third position for opening a circulation valve above the sample chamber.
The disconnecting mechanism also includes a mechanical locking means to prevent the disconnected operating mandrel from moving in the opening direction. Thus, the sampler is locked in the closed position both hydraulically and mechanically.
The operating mechanism for the ball valve is further arranged for selectively disconnecting one of the ball valves for operating the apparatus as a hydraulically controlled safety closure valve.